Rear Derailleur clearence

I have a 2010 or 02011 KettWiesel Allround with triple 30/40/53 rings and 11-34 cassette Shimano thumb shifters.
Has any one found a way to use a medium rear derailleur to increase ground clearance? Will need a way to handle the chain, 42T from smallest to biggest. Prefer to stay away from a Rolloff or Nexus hub unit, but would like more ground clearance under rear derailleur for off road riding.

3 ideas:
The reason why you need a long cage are the extreme gears: 30-11 ad 53-34 in your case. Those shouldn't be used anyway and they are not needed because other gears which don't result in a diagonal chain have the same ratio. If you don't use these gears you can shorten the chain and use a rear derailleur with a shorter cage. The problem is, that if you then accidently try to use these gears you might drop the chain or can even demage the derailleur.
If you have Hase's chain tensioner (for quick lenght changes) it will support the deraillieur.
You can try to get an EGS deraillieur which will give you more clearence without chaning the chain capacity. But they are about 12 years old and hard to find.

3 ideas:
The reason why you need a long cage are the extreme gears: 30-11 ad 53-34 in your case. Those shouldn't be used anyway and they are not needed because other gears which don't result in a diagonal chain have the same ratio. If you don't use these gears you can shorten the chain and use a rear derailleur with a shorter cage. The problem is, that if you then accidently try to use these gears you might drop the chain or can even demage the derailleur.
If you have Hase's chain tensioner (for quick lenght changes) it will support the deraillieur.
You can try to get an EGS deraillieur which will give you more clearence without chaning the chain capacity. But they are about 12 years old and hard to find.

How would a triple front and short derailleur work with road gears 12-26T? Have you seen any issues with this combination?

Well, the math is easy: You would need a capacity of (53-34)+(25-12)=32. A short cage has a capacity of 29, medium cage 36 (or so, depends of the exact make and year I guess).
So you either need a medium cage or apply idea 2 or consider thaught 1 from above.

Shot cage Rear Derailleur

I have a 2010 or 02011 KettWiesel Allround with triple 24/42/53 rings and 11-34 cassette Shimano thumb shifters.
Has any one found a way to use a medium rear derailleur to increase ground clearance? Will need a way to handle the chain, 29T from smallest to biggest. Prefer to stay away from a Rolloff or Nexus hub unit, but would like more ground clearance under rear derailleur for off road riding.

I decided to try a short cage rear Derailleur. I installed a RD 6700-A Shimano Ultegra short cage, made a few changes on the Quick adjust assembly. After adjusting the thumb shiftier for the 11/34 cassette I then took for several rides, total 30 plus miles after a few tweaks now works as well as the original long cage. I can go to the big big rings with out any problem should I accidentally go there. This gives me the increase ground clearance I was after. In one word GREAT.

The post was edited 1 time, last by wafgokett: Now over 400 miles with short cage derailleur, still working great (Aug 23rd 2013, 6:30pm).